Silicon-Containing Electrolyte Additive for Lithium Battery SEI Formation
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Solution Overview
Problem
Lithium secondary batteries face reduced lifetime and energy storage capacity due to electrolyte decomposition at high temperatures, especially in high-temperature environments encountered during charging and discharging, particularly in electric vehicles and power storage systems.
Innovation Solution
Incorporation of a silicon-containing compound in the electrolyte, represented by a specific formula, which forms a solid electrolyte interface (SEI) on the anode surface, reducing irreversible lithium ion reactions and electrolyte decomposition, thereby enhancing high-temperature stability and lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used in high-temperature environments, then battery operation is possible, but electrolyte decomposition occurs leading to reduced lifetime and stability
Solution Approach 1:
The silicon-containing compound performs preliminary action by forming a stable SEI film on the anode surface before the electrolyte can decompose. This pre-formed protective layer prevents subsequent decomposition reactions, thereby improving both high-temperature stability and extending battery lifetime under thermal stress
Solution Approach 2:
The silicon-containing compound acts as an intermediary substance between the anode and the electrolyte. It mediates the interaction by forming a protective interface layer that prevents direct contact and harmful reactions between the electrolyte and anode, especially under high-temperature conditions
2Quantity of substance
If high-voltage cathode active materials are used to increase energy density, then battery capacity increases, but the electrolyte window narrows making it more vulnerable to decomposition
Solution Approach 1:
The silicon-containing compound serves as an intermediary protective layer on the anode surface, creating a stable interface that prevents electrolyte decomposition even when high-voltage cathode materials are used. This intermediary layer expands the effective electrochemical window stability
Solution Approach 2:
The compound performs preliminary anti-action by preemptively forming a protective SEI film that counteracts the tendency of the electrolyte to decompose at high voltages. This pre-formed barrier prevents the harmful decomposition reactions that would otherwise occur with high-voltage cathode materials
3Power
If instant charging and discharging is performed to meet high power demand, then battery power output increases, but temperature rises sharply reducing battery lifetime
Solution Approach 1:
The silicon-containing compound provides beforehand cushioning by forming a thermally stable SEI film that acts as a protective barrier during high-rate charging and discharging. This pre-formed cushioning layer prevents thermal runaway and decomposition reactions that would otherwise occur during instant charging, thereby extending battery lifetime under high power conditions
Solution Approach 2:
The compound acts as an intermediary thermal barrier between the anode and electrolyte during high-power operation. It mediates heat management by providing a stable interface that prevents thermal degradation, allowing high charging rates without compromising battery lifetime
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The silicon-containing compound improves the high-temperature stability and lifetime characteristics of lithium secondary batteries by forming a thin film on the anode, reducing resistance and preventing electrolyte decomposition, leading to better capacity retention and stability.
Implementation Method 1
the silicon-containing compound of Formula 1 used as an additive of an electrolyte for a lithium secondary battery may form a solid electrolyte interface (SEI) as a thin film on a surface of the anode
Data Source
Figure 1
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AI summary
A silicon-containing compound that improves (high-temperature) lifetime characteristics and high-temperature stability of a lithium secondary battery, an electrolyte for lithium secondary batteries that includes the silicon-containing compound, a lithium secondary battery including the electrolyte, and a method of preparing the silicon-containing compound are provided.